Roof spraying machine



'2 5 O 2 0 1 caoss REFERENCE EMMINER June 15, 1943. T. F. BRACKETT .9

I ROOF SPRAYING MACHINE Filed Feb. 13, 1941 '7 Sheets-Sheet 2 3nventor Yimy 17 fimcksii 2 5 0 2 0 l caoss REFERENCE EXAMINER June 15,1943.- T. F. BRACKETT' 2,321,983

ROOF SPRAYING MACHINE File d Feb. 13,1941 v Shoots Sheqt s 25-0- 0 CROSS REFERENCE EXAMINER June 15, 1943. 'r. F. BRACKETT 2,321,983

' -noor' srmnue lucnnns 7 Filed Feb. 13, 1941 7 4 '1 sheets-sheet 4 Jnmntor 2 5 0 2 0 1 CROSS REERENCE EMMINER June 15, 1943. 'r. F. BRACKETT 2,321,983

' ROOF srnume MACHINE Filed Fgb. 13, 1941 7 Shoots-Shoot s Ill 15\ O in? 3nventor fl QBkucksi 2 5.0 ,2 0 1 CROSS REEERENCE EXAMINER J 5, 9 3- T. F. BRACKETT 2,321,983

v ROOF SPRAYING MACHINE Filed Feb. 13, 1941 7 Sheets-Sheet 7 3maentor W7! Q attorneys Patented June s, 1943;

Tracy I. Brackett, Detroit, Ilch.

corporationofnelaware immoral Detl'bihliclma.

Application February 13, 1941, Serial No. 378,705

13 china. (0]. 91-45) This invention relates to an improved machine for spray painting roofs of automobile bodies and involves the use of a spray gun reciprocated at relatively high speed across the roof surface during body travel on the usual factory conveyor line. It was devised especially for operation on current torpedo styled streamline bodies whose roof and rear wall merge into one long continuous downwardly sweeping curve with the roof contour tapering considerably in height from front to rear.-

It is an object of the invention to provide an arrangement for mantaining the gun nozzle properly aimed at anduniformly spaced from the surface being covered and to follow automatically the changing surface contour presented in the spraying zone.

A further object of the invention is to provide a drive for the high speed reciprocation of the gun with motion transmitting connections unaifectedby adjustment of mm position.

Another object is to provide for adjustment ofgun position by raising or lowering the gun to meet variations in height of roof surface and by swinging the gun to direct it substantially normal to the tangent of the surface curvature,

A still further and important object is to provide for control of gun position adjustments automatically in relation to roof surface presented to the gun so that throughout its operating stroke the gun will be projected or retracted as called for to follow roof contour changes and upon reaching fully projected position at the completion of a body spraying operation will be fully retracted to inoperative position out of the path of the succeeding oncoming body.

In a preferred embodiment of the invention there are employed a pair of relatively movable transverse tracks bridging the path of body travel withoneofthetracksbeingflxedandguidinga reciprocatory drive carriage and the other track being vertically adjustable and supporting a projectible member slidably carried in the reciprocating carriage and hingedly mounflng a gun holder together with a reversible electric motor d:ive for raising and lowering the adjustable track under control primary of an electric eye which receives a beam of light to lower the track and gun assembly until the roof surface enters and interrupts the light beam and which is carried by and movable down with the track so as to follow the recession or variation in height of Figure 1 is a front elevation of the assembled machine: Figure 2 is aside elevation with parts in section; Figure 3 is an enlarged fragmentary view looking toward the right-hand side of the machineasviewedinrigurenl'igure4shows in front elevation a fragment of the machine at the left-hand side of Figure 1; Figure 5 is a side elevation of the left end of the machine as viewed onlinei-loffiguret: I'laure6'isavertical sectiontakenonlinel-iofFi'gur-e4:l"igure7isa horizontal section taken on line 1-1 of Figure 6 with the parts on a slightly larger scale: I'igure 8 is an enlarged front elevation of the gun holder and reciprocating carriage; Figure 9 is a vertical sectiontakenonlineHofI'igureBandFigure 10 is a wiring diaphragm of a simplified form of electrical control circuit suitable for regulating the rise and fall of the track assembly.

The usual factory conveyor system includes a continuously traveling chain indicated at I in the drawing to which are hooked in proper spaced succession, wheeled dollies or trucks, such as shown at 2, for carrying bodies along the several work performing stations in the Paint shop. 'Ihebodyl accordingtocurrentstylinghasa metal roof panel curved both transversely and longitudinally with the longitudinal contour sweeping downwardly toward the rear in conthe rise and fall of roof surface presented to the gim due to longitudinal curvature and conveyor travel are taken care of by a vertical adjustment of the pathpf gun reciprocation and the simultaenoug tilting of for aiming purposes since for any given body styling P p r i ti n of the gun nozzle can be dependent on its vertical position.

'i'heguidetracksincludeaflaedraillanda vertically adjustable rail I both of suitable contour transversely of conveyor travel in conformity to transverse roof curvature and supported at vopposite ends in a built-up framework or superstructure indicated generally by the numeral 8 in bridging relation to the conveyor line. The.

overhead assembly is located at, proper height above the fioor, either by vertical supporting posts shown at I in the drawing or by ceiling suspension connections. Opposite ends of the fixed or lowermost track 4 are bolted or otherwise anchored to the frame and above the fixed track and at each side the frame i has a pair of cooperating spaced parallel bars 9 and It affording a vertical slideway to receive the fiat foot of a bracket II on the adjustable upper track I. The guide bar Ill and bracket II are preferably cut from angle strap material and are fitted with the angularly related flanges of the end bracket slidably bearing on the corresponding flanges of the guide bar. To the inside face of the end bracket are welded an inwardly extending plate I! and the adjacent end of the track 5, the latter being secured also to the plate I! and extending on its side between the two end brackets at opposite sides of the machine. For resisting dis tortion a stiffening tube I2 is positioned above the fiat track and at spaced intervals tie plates l4 welded to each are joined by bolts I! as best seen in Figure 9.

Riding on the top and bottom faces of the vertically adjustable track 5 are a pair of rollers II at the top of a rectangular frame assembly I! which projects slidably through guideways in the reciprocatory carriage It for vertical movement upon relative adjustment of the tracks 4 and 5 and carries a hinged gun holder I! at its lower end. The gun holder is arranged to receive interchangeably detachable spray guns, one for each type and color of paint to be employed selectively. The conventional type of gun can be employed with flexible air operating and paint delivery conduits and a valve trigger for actuation through a pivoted lever from an air cylinder 2| under suitable control. The gun will lie in the holder with its nozzle directed downwardly and its aim dependent upon the tilted position of the hinged holder. Tilting of the holder is in accordance with vertical adjustment of the frame assembly l1 and may be effected by the use of camming levers 22 and 23. The lever 22 has its upper end pivoted on a pin 24 at the top of the frame assembly I! with its outer edge suitably contoured and riding against a roller 25 mounted in a carriage supported bracket 26 and its inner edge tracking a roller 21 on the upwardly projecting lever 23. Resulting relative positions of the parts are illustrated by full lines and broken lines in Figure 9. It will be noted also in Figure 8 that the holder I! and lever 23 are fixed together by the pivot pin 28 and a fastening bolt 2!, the latter passing through an arcuate slot in the lever to enable adjustment of the fixed relation.

The reciprocatory carriage ll may consist of a casting to which are bolted housing shields .and other parts inciuding the wheels II which ride on the top and bottom edges of the fixed track 4. It carries oppositely projecting bumpers or buttons II to engage cushioning cylinders near opposite limits of reciprocation and is coupled by a connecting rod 32 to an endless belt 33 running over spaced apart pulleys l4 and 3|. Thepulley 34 on the left-hand side of the machine, as viewed in Figure l, is mounted on a alidable plate biased by the spring 36 to spread the pulleys and maintaintension on the belt 23. The other pulley" is driven through a gear reduction box 31 and belt 38 from an electric motor 3!. Split variable speed pulleys of conventional type are engaged by the belt 88 and enable the speed of carriage reciprocation to be regulated in time with conveyor travel. Carriage reciprocation proceeds and moves the gun in a transverse path defined by track curvature and relative track adjustment with the drive unafi'ected by the rise and fall of the vertically slidable gun supporting frame assembly.

Projection and retraction of the gun supporting frame assembly I1 is accomplished by shifting the vertical position of the upper track 5 and for this purpose the track ends or guide brackets ll carry S-shaped attachments 40. that on the right side hooking the opposite ends of a chain ll running over upper and lower sprocket wheels 42 and 8 as'best seen in Figure 3 while the left end attachment 40 as seen in Figure 5 connects the opposite ends of a chain 44 engaging upper and lower sprockets 45 and 46 as well as an idler sprocket 41 on the swinging end of an adjustable tensioning lever it and a driving sprocket It on the shaft of a reversible electric motor 50. The uppermost sprockets l2 and 45 at the two sides are keyed on a shaft 5| extending across the machine for operation in unison. To relieve the track drive mechanism from some of the weight of the track assembly a flexible cable}! runs over the upper reach of the chain N between the sprockets l9 and 45 and is joined at one end to the track guide bracket H and at its opposite end to one end of a counterbalancing coil spring 53 whose other end is anchored to a fixed bracket 54.

Control of the driving motdr circuit is partially through upper and lower limit switches 55 and 56 mounted one above the other on the guide bar II. The upper limit switch 55 has an operating arm 51 to open the switch upon engagement at the upper limit of the track 5 by an attachment member 58 carried in fixed adjustment by the track while the lower limit switch 56 has a similar arm 59 to be engaged at the lower track limit by a track carried abutment 60 also in adjusted fixed position. A third switch 6| has .an operating arm 62 biased toward closed position and rocked to opened position upon engagement by a pivoted cam plate 61 having a latching pin 64 engageable with a spring pressed latching lever 65 for holding the plate in either switch closed or switch opened position, shown respectively, by full lines and broken lines in Figure 6. At one end the cam plate 63 carries a laterally'projecting pin 66 to be engaged by a rock lever 61 link connected with the solenoid It so that actuation of the solenoid swings the lever 61 from the dotted line position shown and exerts a downwardly pressure on the pin 68 to cam back the latch lever 65 and allow the plate 63 to reach its full line position in which it is again latched. At its opposite end the plate 63 is connected to a vertically extending rod 89 which is part of a manually actuated linkage for emergency control of the switch. Surrounding the rod 69 is a coil spring 1! bearing at its lower end on the cam plate 03 and engageable at its upper end by a lateral ear 1| carried with the vertically movable track and arranged to rock the plate I to inoperative position at a predetermined point in the descent of the track.

ering of the track assembly brings the spray gun m with Proper sp ayin distance the light source and eye are brought into position in which 'thebodyinterruptsthebeamof lightanddownward track movement stops until the light beam aga n pl y on the eye and a resulting follow-up action carries on automatically as called'for by root contour. The lighting unit is shown in the drawing at I2 suspended from the adjustable track assembly by atie rod 13 and bolted toa guide block 14 which is slidable on a dependent post II fixed to the machine frame. A similar guide post II on the opposite side of the machine slidably receives the slider It carrying the photocell 11 and being tied by the strap II to the movable track assembly.

For a better understanding of the operation of the machine a simple wiring diagram is shown in-Flgure 10. The reversible three phase motor I for raising and lowering the track receives current through a main line switch It anda spring return relay operated reversing switch I with a second relay switch 8i controlling current flow for track raising operation of the motor. The coil for the last mentioned switch is in series with the upper limit switch 55 in the secondary circuit containing the transformer 02. The lower limit switch It is in series with the third switch II and the light source I2. Light from the bulb l2 actuates a photocell II to control the switch relay ll, there being a time delay device II in the relay circuit. A starting switch It controls the solenoid 68' for releasing th latch cam plate 03 for closing the light circuit. When the machine is awaiting ior a body to come into the spray none the light I! is out and the vertically adjustable track assembly is raised with the top limit switch I! open. The third switch II in series with the light is latched open by the mechanical means and is unlatched by the actuation of the solenoid I receiving current from the starting switch ll.

Assuming the main line switch II to be closed and the leading roof edge of a traveling body brought into the spray zone. the operator, either manually or through the starting switch 84, releases the plate 03 thereby closing the line circuit and the beam reaches the phototube 11. The relay switch at controlled by the phototube closes the circuit to the motor it causing down movement of the track assembly and with it the phototube and light source, which downward movement continues until the beam is broken by interierence oi the roof contour. Instead of instantly reversing and going up a time delay is introduced into the circuit through the device 03 which is adjusted to conveyor line speed in a manner that if the roof curve is steep enough light impulses reaching the phototube will keep the motion principally downward thus saving wear and tear on the motor and connecting mechanism. The gun nozzle, therefore. iollows the downward sweep of the roof until the spray none is passed by the body and as bottom position of the track assembly is reached the third switch is again latched open. As soon as the track assembly left its top limit position, the top limit switch ll closed and energization of the relay ll conditioned the motor circuit, as controlled by the reversing switch II, for upward track movement. Therefore, with the opening of the third switch ti and deenergization of the relay ll the whole mechanism rises to the top and awaits for the next body.

The top and bottom limit switches are safety features with the top limit switch p ning the motor circuitatswitch ll whenthetrackreaches fully retracted position and the lower limit switch Op ning the light circuit ii the third switch fails to latch open at the bottom track limit. As a furthersaietyieaturethecircnltsare arrangedso that should either the light or phototube fail, the tube controlled reversing switch 80 will be pulled back by its spring and close the motor circuit for raising the assembly out of the path of the oncoming body.

The net result of the control is to cause the gun to follow roof contour within approximately one-half of an inch and to tilt to the predetermined compromise angle for squaring up with the roof curve for varying heights.

While only a preferred embodiment of the invention has been described as employed for painting automobile body roofs it will be evident that various modifications and uses may be made such as come within the scope of the appended claims.

I claim:

1. A machine for spray painting the longitudinally curved roof surface of an automobile body, including a conveyor system for imparting continuous travel to the body in the direction of said longitudinal curvature, a fixed transverse track bridging the path of body travel, a carriage mounted for reciprocation on and guided by said fixed track. a spray gun carrying member vertically slidably mounted in said carriage, a member engaging rail extending in parallel relationto said track and being vertically adjustable for regulating the projection and retraction of the gun carrying member in relation to said carriage and means responsive to variations in height of the body roof surface presented at the spray zone for shifting the position of the adjustable rail to follow the contour of the body roof surface presented at the spray zone.

'2. A machine for spray painting the longitudinally curved roof surface of an automobile body, including a conveyor system for imparting continuous travel to the body in the direction of said longitudinal curvature, a fixed transverse track bridging the path of body travel. a carriage mounted for reciprocation on and guided by said fixed track, a spray gun carrying member vertically slidably mounted in said carriage, a member engaging track extending parallel to the fixed track and being vertically adjustable for regulating the projection and retraction oi the gun carrying member in relation to said carriage, means responsive to variations in height of the body roof surface presented at the spray zone to adjust said track, a spray gun'holder pivotally mounted on said slidable member on an axis extending transversely of the path of body travel and cam mechanism operable upon movement of the adjustable track relative to the fixed track toswing the gun holder about its pivot.

and from the fixed track, a gun holder pivotally mounted on the member on an axis extending transversely of the plane of sliding movement of said member and cam means operable to tilt said holder as an incident to relative track adjustment.

4. In a machine for spray painting the curvilinear wall surface of a body traveling through the spray zone, a carriage, a fixed track mounting the carriage for reciprocation and running in a direction generally parallel to the wall surface and transverse to the path of body travel, a slider mounted on the carriage for movement relative thereto in a direction transverse to the direction of carriage reciprocation and toward and away from the path of body travel, an adjustable track extending substantially parallel to the fixed track and being engaged by the slider to position the same, means for shifting the adjustable track toward and from the fixed track to vary the position of said slider, a gun holder pivoted on the slider on an axis transversely related to the direction of slider movement, a cam rail hinged to the slider and engaged by an abutment on the carriage for the swinging thereof upon slider projection and a motion transmitting connection between the hinged rail and the pivotal gun holder.

5. In a machine for spray painting the curvilinear wall surface of a body traveling through the spray zone, a pair of substantially parallel tracks extending transversely to the path of body travel and being relatively adjustable toward and from one another, a carriage mounted for reciprocation on one of the tracks, a member riding on the other track, means mounting said member in the carriage for projection relative thereto toward and away from the path of body travel, a gun holder hinged on said member for swinging movement about an axis extending substantially parallel to the direction of carriage reciprocation and means to swing the gun holder coincident with the projection of said member upon relative adjustment of the pair of tracks, said means including a motion transmitting interconnection between the gun holder and the carriage through which the projection of the member relative to the carriage is transmitted to tilt the gun holder.

6. In a machine for spray painting the curvilinear wall surface of a body traveling through the spray zone, a pair of tracks extending substantially parallel to one another and to the body wall surface and transversely to the path of body travel, means mounting the tracks for relative adjustment toward and from one another, a carriage mounted for reciprocation on one of the tracks, a member slidably mounted in the carriage for projection toward and from the path of body travel, guide means on the member arranged to ride on the other track for projecting the member relative to the carriage, a gun holder hinged on said member on an axis extending substantially parallel to the tracks, a rock lever carried by the projectible member and slidably engageable with an abutment on the carriage for rocking the lever upon member projection relative to the carriage and means to transmit lever motion for tilting the gun holder.

7. Mechanism for spray painting the longitudinally curved roof surface of an automobile body and for universal use with various types of bodies differing in roof contour, including a spray gun, a conveyor system for imparting continuous longitudinal travel of the body under the gun,

mechanism for reciprocating the gun transversely across the traveling roof surface, means for adjusting the vertical position of the gun to maintain substantially uniform spray distance, other means to tilt the gun about an axis transverse to the path of body travel for aiming the same and roof contour tracing means including a light sensitive cell operative directly on the roof surface to detect its height and directly responsive to changes in height of the roof surface presented to the gun for actuating the last two mentioned means.

8. Mechanism for spray painting the'longitudinally curved surface of a body traveling longitudinally through the spray zone, including a spray gun reciprocable transversely of the path of body travel, a gun support shiftable toward and from the path of body travel, electrically actuated means to shift the support, a photocell control for said means arranged to actuate the same for shifting the gun support in follow-up relation to changing body surface contour and thereby maintain substantially uniform spray distance between said surface and the spray gun, said control being responsive to the presentation of body surface in the spray zone and including a light sensitive cell and a light source focusing on the cell a light beam projected across the path of body travel and means mounting said control for movement with the shiftable gun support in follow up relation to changing body surface contour.

9. Mechanism for spray painting the longitudinally curved surface of a body traveling longitudinally through the spray zone, including a gun support, means mounting the gun support for adjustment inwardly of the path of body travel, an electrical device for regulating adjustment of the support, and a controller therefor including a light sensitive cell carried by the support on one side of the path of body travel, switching means controlled by the cell to regulate current flow to said device for actuating the same to move the support in one direction when the cell receives a light beam and to reverse the direction of support movement when the light beam to the cell is interrupted and a light source carried by the support on the opposite side of the path oi body travel and focused on said cell for interruption of the light beam by a body traveling therethrough.

10. Mechanism for performing work on a longitudinally curved surface of a body traveling longitudinally through the work zone, including a work performing device. a support therefor reciprocable in a direction toward the path of body travel, electric drive means operable normally to project the support in a direction to cause the work performing device to approach the work surface, a photocell control for the drive means including a light sensitive device and a light projector focused on said device with its beam projecting on a line to be intercepted by the work surface presented in the working zone to check said approach and means mounting the control for movement with the adjustable support in following work surface contour brought into the work zone as the body travels therethrough. i

ll. .The structure of claim 10 together with means operable automatically when the support reaches its innermost limit to render the photocell control ineffective and enable retraction of the support to its outermost limit.

12. A spray painting machine for operation on objects traveling through the spray zone of the machine including a spray gun support, means mounting the support for projection and retraction toward and from the path of the traveling objects to be painted to maintain substantially uniform spraying distance, a reversible electric motor for actuating said support, a switch for the motor biased toward retracting position, a photocell control movable with the gun support and operable to actuate said switch to projecting position, a source of light'also movable with the gun support for directing and actuating light beam to said photocell control and arranged to be blanked out by the object being painted when' the support is projected into given spray distance, and a limit switch operable as the gun support reaches its limit of projection to render the photocell control inoperative.

13. A machine for spray painting the longitudinally curved roof surface of an automobile body, a conveyor system for moving the body in the direction of its longitudinal curvature, a track to guide and support a spray gun reciprocable across the roof surface in a direction transverse to the direction of body travel, means including a light sensitive cell to detect the height of the roof surface presented to the gun and other means responsive to said detector means for shifting said track vertically to maintain a substantial uniform spray gun distance.

TRACY F. BRACKEI'I. 

